Sampling filter for chlorinated organic compounds

ABSTRACT

A collector  3  capable of collecting and sampling simultaneously various types of chlorinated organic compounds in both particulate and gaseous forms contained in a fluid and easy to extract the sampled chlorinated organic compounds therefrom includes a sampling filter  7  installed in a holder  6  having a discharge route  12   a . The sampling filter  7  contains fibers and an inorganic binder for binding the fibers to one another and has a fluid-permeability. Various types of the chlorinated organic compounds such as dioxins and coplanar PCBs in both particulate and gaseous forms contained in a sample gas flowing into the holder  6  from a flue duct  25  through a sampling pipe  2  and an introduction pipe  8  are collected and sampled while the sample gas being passed through the sampling filter  7  and the resulting sample gas from which the chlorinated organic compounds are removed is then discharged out to the outside through the discharge route  12   a.

FIELD OF THE INVENTION

The present invention relates to a sampling filter for chlorinatedorganic compounds, especially a filter for removing chlorinated organiccompounds contained in a fluid from the fluid and sampling them.

BACKGROUND ART

A waste gas generated from incineration facilities for incineratingwastes such as industrial wastes and domestic refuse contains varioustypes of chlorinated organic compound such as dioxins, coplanar PCBs,and further polychlorobiphenyl, chlorophenol and chlorobenzene.

Here, the word, dioxins, is a general term ofpolychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofuran (PCDFs), andthe like and as known well, they are extremely toxic environmentalpollutants and especially tetrachlorodibenzodioxins (T₄CDDs) among themis known as the most intensely toxic environmental pollutant. Further,polychlorobiphenyls are also strongly toxic environmental pollutants andcoplanar PCBs among them is recognized similarly as the most intenselytoxic environmental pollutant. On the other hand, although chlorinatedorganic compounds such as chlorophenol, chlorobenzene and the like areless toxic than dioxins, they are recognized as environmental pollutantsjust like dioxins since they are found easy to be converted into dioxinsusing various element contained in fly ashes as catalyst in, forexample, an incinerator in a temperature range of the waste gas. Forthat, in terms of the environmental preservation, it becomes an urgentissue to establish a countermeasure for removing such variouschlorinated organic compounds as described above from a fluid such as awaste gas and wastewater and at the same time it is also urgent toestablish a technique of analysis of such chlorinated organic compoundscontained in a fluid in global scale.

At the time of analyzing chlorinated organic compounds contained in afluid, at first, a sample has to be taken precisely and accurately froma fluid to be an object for the analysis. For example, in the case ofanalysis of chlorinated organic compounds contained in a waste gas, aprescribed amount of a sample gas is sampled from a space containing thewaste gas, for example, a flue duct to pass the waste gas through andvarious chlorinated organic compounds contained in the sample gas arerequired to be reliably collected without leakage. Especially, sincedioxins and coplanar PCBs, environmental pollutants as described above,are contained extremely slight in amounts in the sample gas andregardless of the existence forms such as particulate form or gaseousform, the types varies widely, failing precise sampling, highly reliableanalysis results cannot be expected. Further, the above-describedcoplanar PCBs is contained in a large amount in atmospheric air and ifthe sample gas is contaminated with such coplanar PCBs, highly reliableanalysis results cannot either be expected. For that, in order toguarantee the accuracy of the analysis results, Japan, US, and eachcountry of Europe respectively have been officially regulating thesampling methods of samples necessary to analyze the chlorinated organiccompounds such as dioxins and coplanar PCBs contained in, for example, awaste gas.

For example, the Japanese Industrial Standards JIS K 0311: 1999formulated on Sep. 20, 1999 regulates, “A measurement method of dioxinsand coplanar PCBs in waste gas” and practically exemplifies a samplingapparatus of a sample gas containing chlorinated organic compounds suchas dioxins. The sampling apparatus is provided with a sampling tube forsampling a sample gas from a flue duct in which a waste gas of anincinerator flows through, a first collector equipped with a filter unitfor sampling the chlorinated organic compounds mainly in a particulateform contained in the gas sampled in the sampling tube, and a secondcollector for sampling the chlorinated organic compounds in a gaseousform difficult to be sampled by the first collector. In this case, thesecond collector is provided with mainly a liquid collecting sectioncomposed of a plurality of impingers made of glass and filled with anabsorption liquid and an adsorptive collecting section containing anadsorbent (e.g. XAD-2) so as to collect the chlorinated organiccompounds in the gaseous state, which are not collected by the firstcollector, by the absorption liquid and the adsorbent.

Such a sampling apparatus has a complicated constitution comprising thefirst collector and the second collector and is costly owing to the useof many appliances made of glass, so that in many cases, the apparatusis used repeatedly. In such a case, since it is required to keep therespective members such as impingers clean in order to retain thereliability of the measurement data, the preparatory operation such as awashing work and the like to be carried out before sampling of a samplegas becomes extremely complicated. Further, at the time of sampling thegaseous chlorinated organic compounds contained in the sample gas by thesecond collector, the second collector is required to be cooled by acooling material such as dry ice and the sample-sampling operationitself becomes extremely complicated, too. Further, after the samplingof the sample gas, the chlorinated organic compounds collected by thefirst collector and the second collector are needed to be extracted andin this case, the chlorinated organic compounds separately collected bythe first collector and the second collector are needed to be extractedseparately. Therefore, the extraction operation itself becomescomplicated and takes a long time to finish and further the reliabilityof the analysis results is, in many cases, affected by the skills of theextraction operation. Further, the sampling apparatus comprises twotypes of collectors, the first collector and the second collector, sothat the apparatus is inevitably enlarged, and also glass appliances areused a lot, therefore the apparatus is easy to be broken to makehandling and transportation difficult at the time of sampling the samplegas.

On the other hand, Environment Preservation Agency (EPA) of USA. andComite de Europeen Normalisation (CEN) have determined official methodsindependently and the sampling apparatuses described therein are not somuch different from the Japanese one described above in terms of thecomplication of the constitution and the difficulty of handling althoughthere exist miner difference in details.

The object of the present invention is to simultaneously collect andsample various kinds of chlorinated organic compounds in bothparticulate form and gaseous form and easily extract the sampledchlorinated organic compounds.

DISCLOSURE OF THE INVENTION

A sampling filter for chlorinated organic compounds according to thepresent invention is for removing chlorinated organic compoundscontained in a fluid from the fluid and sampling them, and comprises afluid-permeable molded body containing fibers and an inorganic binderfor binding the fibers to one another. In this case, the molded body hasa bulk density of, for example, 0.1 to 1 g/cm³. Further, the fibers areof at least one kind of fibers selected from a group consisting offibrous activated carbon, carbon fiber, glass fiber, alumina fiber,silica fiber and Teflon fiber. The inorganic binder has an adsorbingcapability to, for example, chlorinated organic compounds. In this case,the inorganic binder is of at least one kind of compounds selected froma group consisting of alumina, zeolite and silicon dioxide.

In one embodiment of a sampling filter for the chlorinated organiccompounds according to the invention, the above-described fibers areactivated alumina fibers and the above-described inorganic binder is agranular activated alumina. In this case, the bulk density of theabove-described molded body is, for example, 0.3 to 0.7 g/cm³.

Since the sampling filter of the invention is of a fluid-permeablemolded body, a fluid containing various types of chlorinated organiccompounds such as dioxins and coplanar PCBs in both particulate form andgaseous form can be passed through. At that time, the various types ofchlorinated organic compounds in both forms are collected simultaneouslyby the fibers and the inorganic binder contained in the molded body tobe separated from the fluid. That is, various types of the chlorinatedorganic compounds in both particulate and gaseous forms contained in thefluid are sampled by the molded body. The sampled chlorinated organiccompounds are extracted by a variety of extraction operations for theresulting molded body.

The production method of the present invention is a method for producinga filter for removing chlorinated organic compounds contained in a fluidfrom the fluid and sampling them, and comprises steps of producing amolding material containing fibers and an inorganic binder for bindingthe fibers to one another and molding the molding material into aprescribed shape and then sintering the molded material. The productionmethod further comprises, a step of, for example, immersing the obtainedmolded body in an aqueous dispersion of an inorganic binder and thendrying it.

In the production method, since the molding material is sintered afterbeing molded as described above, a molded body having afluid-permeability can be produced. Since the molded body contains thefibers and the inorganic binder, when a fluid containing various typesof chlorinated organic compounds such as dioxins and coplanar PCBs inboth particulate and gaseous forms passes through, the molded body cancollect simultaneously various types of chlorinated organic compounds inboth forms to remove them from the fluid.

A collector of the chlorinated organic compounds according to thepresent invention is for collecting the chlorinated organic compoundscontained in a fluid flowing in a transportation pipe, and comprises afilter of a fluid-permeable molded body and a container for housing thefilter and having a discharge outlet for discharging the fluid passedthrough the filter to the outside. The filter contains fibers and aninorganic binder for binding the fibers to one another. The filter has,for example, a cylindrical shape with an opening part to insert thetransportation pipe into in one side and closed in the other side.

In the collector, the fluid from the transportation pipe is dischargedthrough the discharge outlet to the outside after being passed throughthe filter in the container. At that time, various types of thechlorinated organic compounds such as dioxins and coplanar PCBs in bothparticulate and gaseous forms contained in the fluid are simultaneouslycollected by the fibers and the inorganic binder, separated from thefluid and sampled by the filter. The various types of the chlorinatedorganic compounds sampled by the filter are extracted by a variety ofextraction operations for the filter.

A sampling method of chlorinated organic compounds according to thepresent invention is a method for sampling chlorinated organic compoundscontained in a fluid flowing in a transportation pipe, and comprises astep of passing a fluid from the transportation pipe through a filter ofa fluid-permeable molded body containing fibers and an inorganic binderfor binding the fibers to one another.

Since the sampling method is carried out using said filter of thefluid-permeable molded body containing the fibers and the inorganicbinder for binding the fibers to one another, when the fluid from thetransportation pipe passes through the filter, the various types of thechlorinated organic compounds such as dioxins and coplanar PCBs in bothparticulate and gaseous forms contained in the fluid are simultaneouslycollected and sampled by the filter. The various types of thechlorinated organic compounds sampled by the filter are extracted bycarrying out a variety of extraction operations for the filter.

Other objects and effects of the present invention will be made clearfrom the following detailed descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic constitutional figure of a sampling apparatus ofchlorinated organic compounds which employs a collector relevant to oneembodiment of the invention;

FIG. 2 is a front view of the collector;

FIG. 3 is a vertical cross-sectional figure of the collector;

FIG. 4 is a IV-IV cross-sectional figure of FIG. 2; and

FIG. 5 is an electron microscopic photograph of a part of the moldedbody obtained in Example 1.

DETAILED DESCRIPTION OF THE INVENTION

A schematic constitution of a sampling apparatus for chlorinated organiccompounds is shown in FIG. 1 which employs one embodiment of collectorsof chlorinated organic compounds according to the invention. Thesampling apparatus 1 is for sampling chlorinated organic compoundscontained in a sample fluid such as a waste gas (a sample gas) amongfluids. In the figure, the sampling apparatus 1 mainly comprises asampling pipe 2, a collector 3 (one embodiment of collectors accordingto the invention), and an aspirator 4.

The sampling pipe 2 is a pipe made of, for example, borosilicate glassor transparent quartz glass and having a cooling apparatus 5 for coolingthe sample gas flowing therein.

With reference to FIGS. 2, 3, and 4, the collector 3 will be describedin details. In the FIGS., the collector 3 is provided mainly with aholder (one example of a container) 6, a sampling filter 7 (oneembodiment of a sampling filter for chlorinated organic compoundsaccording to the invention) for collecting and sampling the chlorinatedorganic compounds contained in the sample gas and installed in theholder 6, an introduction pipe 8 (one example of a transportation pipe)for introducing the sample gas transported through the sampling pipe 2into the sampling filter 7, and an installation unit 9 for installingthe introduction pipe 8 in the holder 6.

The holder 6 is an approximately cylindrical container made oftransparent glass and comprises mainly a main body unit 10 capable ofhousing the sampling filter 7 in, an installation section 11 forinstalling the installation unit 9, and a gas discharge section 12 fordischarging the sample gas.

The installation section 11 is integrally formed in the end part of themain body unit 10 and its diameter is narrowed as compared with the mainbody unit 10. The installation section 11 has a spiral groove 11 aformed in the outer circumferential face and an opening part 11 b in anend part.

The gas discharge section 12 is integrally formed in the other end partof the main body unit 10 and comprises a discharge route (one example ofa discharge outlet) 12 a for discharging the sample gas to the outsideand a branch route 12 b. The branch route 12 b is for inserting atemperature measuring apparatus 27 (FIG. 1) such as a thermometer and athermocouple for measuring the temperature of the sample gas passingthrough the gas discharge section 12 into the gas discharge section 12.

The sampling filter 7 is a cylindrical porous molded body closed in oneend and having an opening part 7 a for introducing the sample gas in theother end, in other words, a porous cylindrical filter and the openingpart 7 a side is supported by the installation unit 9, whereas theclosed end side is inserted into the main body unit 10 of the holder 6from the opening part 11 b. The sampling filter 7 is not necessarilyrestricted in the size, however generally it is so formed as to have 50to 150 mm in the length, 12 to 35 mm in the outer diameter of the endpart in the opening part 7 a side, 10 to 30 mm in the outer diameter ofthe closed end side, 1 to 10 mm in the thickness and is so tapered as tohave an outer diameter in the closed end side narrower than the outerdiameter of the end part in the opening part 7 a side. Incidentally, thedetails of the sampling filter 7 will be further described later.

The introduction pipe 8 is a tubular member made of glass as same as theholder 6 and made detachable to the opening part 7 a of the samplingfilter 7. That is, the introduction pipe 8 has a joining part 13 forjoining the end part of the sampling pipe 2 in one end and is insertedinto the opening part 7 a of the sampling filter 7 while penetrating theinstallation unit 9 in the other end in a detachable manner.

The installation unit 9 comprises a first supporting unit 14 forsupporting the sampling filter 7 in the holder 6 and a second supportingunit 15 for installing the introduction pipe 8 in the first supportingunit 14. The first supporting unit 14 is made of a resin or a metal andhas a hole part 14 a for supporting the end part of the opening part 7 aside of the sampling filter 7. In the inner circumferential face of thehole part 14 a, a spiral groove 14 b is formed. The first supportingunit 14 is fixed in the spiral groove 11 a of the installation section11 side of the holder 6 by screwing with the spiral groove 14 b.Further, the first supporting unit 14 has a projected unit 16 projectedin the left direction in FIG. 3. The projected unit 16 has a throughhole 16 a to enable the tip end of the introduction pipe 8 to beinserted into and a spiral groove 16 b in the outer circumferentialface.

On the other hand, the second supporting unit 15, a unit made of a resinor a metal as same as the first supporting unit 14, is formed to be likea cover having a spiral groove 15 a in the inner circumferential faceand has a through hole 15 b to insert the introduction pipe 8 into. Thesecond supporting unit 15 is fixed in the spiral groove 16 b of theprojected unit 16 of the first supporting unit 14 by screwing with thespiral groove 15 a while the introduction pipe 8 being inserted into thethrough hole 15 b.

The sampling filter 7 installed in such a collector 3 can be detachedfrom the holder 6. In this case, the second supporting unit 15 of theinstallation unit 9 is detached from the first supporting unit 14 andthe introduction pipe 8 is pulled out the sampling filter 7. When thefirst supporting unit 14 is detached from the holder 6, the samplingfilter 7 can be taken out of the holder 6 while being supported by thefirst supporting unit 14.

The aspirator 4 is provided with a gas discharge route 20 and a suctionapparatus 21. The gas discharge route 20 is joined to the dischargeroute 12 a of the collector 3 using a tubular joint 22 in one end andhas a cooling apparatus 23 and a trap 24 in this order from thecollector 3 side. The suction apparatus 21 is attached to the other endof the gas discharge route 20 and comprises a suction pump 21 a and agas meter 21 b in this order. The suction pump 21 a has a flow rateadjusting function and is possible to be used continuously for 24 hoursor longer. The gas meter 21 b is for measuring the flow rate of thesample gas and is capable of measuring the flow rate in a range of 10 to40 l/min with accuracy of 0.1 l/min level.

Next, the sampling filter 7 to be employed for the above-describedcollector 3 will be described in details. The sampling filter 7 is of amolded body having a three-dimensional mesh structure and afluid-permeability (in this example, a gas-permeability).

The molded body composing the sampling filter 7 contains fibers (a groupof fibers) and an inorganic binder. The fibers to be employed in thiscase are those which do not substantially cause chemical reactions withthe various types of the chlorinated organic compounds such as dioxins,their precursor, and coplanar PCBs. Examples of the fibers includefibrous activated carbon, carbon fiber, glass fiber, alumina fiber(especially activated alumina fiber), silica fiber, and Teflon fiber.These fibers may be used solely or in combination of two or more typesof them. The fiber diameter and the specific surface area of the fibersare not particularly restricted.

Incidentally, the average aspect ratio (the length/the diameter) of thefibers may 10,000 or lower, especially preferably 1,000 to 10,000. Ifthe average aspect ratio of the fibers exceeds 10,000, the pressure lossincreases during the time of sampling a sample fluid (a sample gas) topossibly result in incapability of isokinetic suction standardizedaccording to the above-described JIS standards (JIS K 0311:1999).

On the other hand, the inorganic binder contained in the molded body hasa property for binding the fibers to one another to integrate a group ofthe fibers and give a prescribed molding shape to the group of fibers,that is, has a function as a binder for maintaining the prescribedmolding shape of the group of fibers. To say more practically in thisembodiment, it is for setting the group of fibers to be the shape ofsaid sampling filter 7, in other word, a cylindrical shape with closedone end.

An inorganic binder usable in this case is not particularly restrictedif it has said properties and does not substantially cause chemicalreactions with the fibers as well as chlorinated organic compounds,however those having an adsorbing capability, especially a chlorinatedorganic compounds-adsorbing capability are preferable. As such ainorganic binder having adsorbing capability, examples are alumina(especially, activated alumina), zeolites, silicon dioxide (silica),acidic white clay, apatites and the like. The respective inorganicbinders may be used solely or in combination of two or more of them.Further, although the form of the inorganic binders is not specificallyrestricted, generally, those with a granular shape are used.

In this case, the zeolites are hydrated aluminosilicates having ageneral formula, X_(m)Y_(n)O_(2n).sH₂O, and in the general formula, thereference character X denotes Na, Ca or K; the reference character Ydenotes Si+Al, respectively; and the reference character S is notconstant. As such zeolites, synthetic zeolites are preferable to beused.

Among said inorganic binders, in this invention, those having atar-adsorbing capability are especially preferable. If inorganic bindershaving such characteristics are used, the sampling filter 7 caneffectively adsorb tar (details of it will be described later), forexample, produced and derived from carbon monoxide contained in thesample gas and accordingly reliably collect and sample the various typesof the chlorinated organic compounds such as dioxins and coplanar PCBsdissolved in the tar. Incidentally, examples of the inorganic binderscapable of adsorbing tar include alumina, zeolites and silicon dioxide.As the alumina, activated alumina is especially preferable to be used.These inorganic binders capable of adsorbing tar may be used solely orin combination of two or more of them.

The molded body containing the above-described fibers and inorganicbinder is preferable to have a bulk density preferably set to be 0.1 to1 g/cm³, more preferably 0.3 to 0.7 g/cm³. If the bulk density of moldedbody is below 0.1 g/cm³, some of chlorinated organic compounds containedin the sample gas are sometimes passed through the sampling filter 7 andthat makes it difficult to carry out sampling of chlorinated organiccompounds contained in the sampling gas without substantial leakage.Contrary, if the bulk density exceeds 1 g/cm³, the pressure loss isprobably increased in the sampling filter 7 at the time of collectingthe particulate substances contained in the sampling gas to possiblyresult in incapability of isokinetic suction standardized according tosaid JIS standards (JIS K 0311:1999). Further, in the extractionoperation, which will be described later, for extracting the chlorinatedorganic compounds sampled by the sampling filter 7, the extraction ratiois possibly decreased.

The preferable molded body composing the sampling filter 7 is thosecomprising activated alumina fibers as the fibers and a granularactivated alumina as the inorganic binder. Especially, the mostpreferable one is such a molded body so formed as to have the bulkdensity in a range of 0.3 to 0.7 g/cm³.

The sampling filter 7 of the above-described molded body can beproduced, for example, by the following manner. At first, a moldingmaterial containing the above-described fibers and inorganic binder isprepared. In this case, a dispersion containing an inorganic binderdispersed in water is produced and the fibers are added to thedispersion and the inorganic binder and the fibers are evenly mixed. Atthat time, the mixing ratio of the fibers and the inorganic binder ispreferable to be adjusted properly so as to keep the bulk density of theaimed molded body within said range.

Next, the obtained molding material is molded in a prescribed shape,that is, a one end-closed cylindrical shape to obtain a molded body. Asthe molding method employed in this case, a variety of well knownmolding methods, for example, a wet die molding method and the like maybe employed. Then, the obtained molded body is sintered by heating toobtain the aiming molded body, that is, a sampling filter 7. Thetemperature at the time of sintering is not specifically restricted,however, in the case alumina is used for either one or both of thefibers and the inorganic binder, the temperature is preferable to be setin a range in which the alumina is activated and converted intoactivated alumina, that is, practically 150 to 700° C.

The molded body produced in the manner as described above may further beimmersed in an aqueous dispersion containing an inorganic binderdispersed in water and then dried. If such treatment is carried out forthe molded body, the molded body is impregnated with the inorganicbinder and a molded body containing the inorganic binder in a largeramount can be produced. Further, by way of such treatment, the bulkdensity of the molded body can be adjusted to be within said preferablerange. Since the inorganic binder is consequently contained in a largequantity by such treatment, in the case of using an inorganic binderhaving said tar-adsorbing capability, the chlorinated organic compoundscontained in the sample gas can be collected without leakage even if alarge quantity of unburned hydrocarbons, which will be described later,and carbon monoxide are contained in the sample gas. Incidentally, thedrying method for the molded body is not particularly restricted,generally, it is preferable to employ a method for removing water byheating the molded body at 150 to 700° C.

Next, a use method of the sampling apparatus 1, that is, a samplingmethod of chlorinated organic compounds using the sampling apparatus 1will be described. In this embodiment, the description will be regardinga case of sampling a sample gas from a waste gas flowing in a space inincineration facilities for incinerating wastes, for example, flowing ina flue duct and sampling the various types of the chlorinated organiccompounds such as dioxins and coplanar PCBs. In this case, as shown inFIG. 1, the tip end of the sampling pipe 2 of the sampling apparatus 1is inserted into a flue duct 25 from a sampling port 25 a formed in theflue duct 25. At that time, a packing 26 is attached to the samplingpipe 2 to air-tightly seal the gap between the sampling pipe 2 and thesampling port 25 a. Further, a temperature measuring apparatus 27 suchas a thermometer and a thermocouple is installed in the branch route 12b in the collector 3.

In such a state, the suction pump 21 a is operated to carry outisokinetic suction of some of the waste gas flowing in the flue duct 25into the sampling pipe 2. At that time, the isokinetic suction amount iscalculated by measuring the temperature, the flow rate, the pressure,and the water amount in the waste gas flowing in the flue duct 25according to JIS Z 8808 and based on the calculation results, thesuction flow rate by the suction pump 21 a is controlled. The flow rateset in this case is preferable to be properly monitored by a gas meter21 b and properly adjusted as to continuously keep the isokineticsuction state.

The sampled gas flowing into the sampling pipe 2 is cooled by thecooling apparatus 5 and generally cooled to the temperature not higherthan the dioxins production temperature, for example, to 120° C. orlower. Consequently, generation of new dioxins can be prevented in thesampling pipe 2.

The cooled sampled gas then flows into the sampling filter 7 afterpassing through the introduction pipe 8 of the collector 3 from thesampling pipe 2. The sampled gas flowing into the sampling filter 7flows out to the main body unit 10 of the holder 6 after passing throughthe sampling filter 7 as shown by the arrow in FIG. 3 and flows towardan aspirator 4 after passing through the discharge route 12 a. At thattime, a various soot and dust and various types of the chlorinatedorganic compounds such as dioxins and coplanar PCBs in both particulateand gaseous forms and contained in the sampled gas are simultaneouslycollected by said fibers and the inorganic binder and sampled from thesampled gas.

In the case a large quantity of carbon compounds such as unburnedhydrocarbons and carbon monoxide (CO) are contained in the sampled gas,tar derived from the carbon compounds is easy to be produced in thesampled gas. In many cases, the tar dissolves the various types of thechlorinated organic compounds such as dioxins and coplanar PCBs thereinand takes them inside. For that, if a filter employing an inorganicbinder having no tar-adsorbing capability, for example, a filter made ofa molded body produced by molding the above-described fibers using anorganic binder such as a cellulose type binder is employed as thesampling filter 7, the filter cannot efficiently collect the tarproduced in the sampled gas and consequently, some of tar contained inthe sampled gas possibly passes through the filter and leaks to theoutside. That is, the chlorinated organic compounds dissolved in the tarare possibly discharged to the outside together with some of the tarwithout being sampled by the filter. That is a phenomenon whichinventors of the present invention have found in the process ofdeveloping the invention and if the amount of the unburned hydrocarbonsis judged using carbon monoxide as an index, especially, in the case thecarbon monoxide concentration in the sampled gas exceeds 150 ppm, it isfound that tar considerably passes through.

On the contrary, the sampling filter 7 according to this embodiment, inthe case the filter is made of a molded body containing theabove-described fibers and an inorganic binder having tar-adsorbingcapability, can collect tar contained in a sampled gas substantiallywithout leakage even if the concentration of the unburned carboncompounds in the sampled gas is high (for example, even in the case theconcentration of carbon monoxide in the sampled gas exceeds 150 ppm). Inother words, the sampling filter 7 can collect and sample the varioustypes of the chlorinated organic compounds such as dioxins and coplanarPCBs in both particulate and gaseous forms contained in the sampled gassubstantially without leakage, regardless of the degree of theconcentration of the unburned hydrocarbons in the sampled gas.

As described above, the sampled gas from which soot and dust and thevarious types of the chlorinated organic compounds in particulate andgaseous forms are removed by the sampling filter 7 substantially withoutleakage continuously flows toward the aspirator 4 from the dischargeroute 12 a. At that time, the temperature of the sampled gas flowing inthe discharge route 12 a is measured by the temperature measuringapparatus 27 installed in the branch route 12 b and controlled.

The sampled gas discharged out the discharge route 12 a flows in the gasdischarge route 20 and further cooled by the cooling apparatus 23.Consequently, water contained in the sampled gas is condensed and storedin the trap 24. The sampled gas from which water is removed in such amanner is discharged to the outside from the gas meter 21 b afterpassing through the suction pump 21 a. Incidentally, sampling of asample gas, that is a waste gas, by the sampling apparatus 1 is carriedout generally for a duration corresponding to the waste gas amountestimated from the detection limit value of the chlorinated organiccompounds (generally, a waste gas of 1 to 3 Nm³/3 to 4 hours).

In the case of analysis of the concentration of the chlorinated organiccompounds contained in the gas (a waste gas) sampled in such a manner,the sampling apparatus 1 is detached from the flue duct 25 and thecollector 3 is isolated from the sampling apparatus 1. Further, thesampling filter 7 is detached from the isolated collector 3.

Then, the sampling pipe 2, the introduction pipe 8, and the holder 6 arewashed using a solvent and the washing liquid at that time is kept. Onthe other hand, the chlorinated organic compounds collected by thesampling filter 7 of the collector 3 are extracted by a solvent. In thiscase, the extraction operation of the chlorinated organic compoundscollected by the sampling filter 7 can be carried out by, for example, acommon Soxhlet extractor. However the sampling filter 7 can be housed ina cell of a high speed extractor if it is set in a small size asdescribed above and using the high speed extractor, the extractionoperation can quickly be carried out. Further, the sampling filter 7does not require the extraction conditions to be set specially in orderto shorten the extraction time if the bulk density of the molded bodycomposing the filter is set within the said range and the collectedchlorinated organic compounds can be dissolved in the solvent quicklywithin a short time.

At the time of analysis of the chlorinated organic compounds, theabove-described washing liquid and the extraction solution obtained bythe extraction operation as described above are mixed and subjected tothe analysis operation. In this case, as the analysis method, forexample, methods employing gas chromatographic mass spectroscopy (GC/MSmethod) may be employed according to a method disclosed in, “Standardmeasurement and analysis manual for dioxins in waste treatment” editedby Environment assessment section, City water environment division, Lifehygiene bureau of the Ministry of Health and Welfare Japan (published inMarch 1997, by Foundation of Waste Research and Investigation) or amethod standardized by Japanese Industrial Standards JIS K 0311: 1999(formulated on Sep. 20, 1999).

In the case another sample gas is sampled using the sampling apparatus1, for example, the collector 3 is replaced with a new one. In thiscase, since the sampling apparatus 1 can be employed for the next gassampling by sufficiently washing only the sampling pipe 2, thepreparatory work before sampling a sample gas is significantly made easyas compared with that carried out using a conventional impinger and thetime taken to sample the sample gas can considerably be shortened andthe cost for sampling the sample gas can greatly be lowered. Further,since the sampling apparatus 1, especially the collector 3, is simple inthe constitution as compared with a conventional complicated samplingapparatus, so that it is easy to handle and transport. For that, usingthe sampling apparatus 1, a sampling work of a sample gas can be carriedout easily even in a flue duct where it is difficult to install aconventional large size sampling apparatus using an impinger.

Incidentally, the collector 3 used once can be re-used repeatedly bysufficiently washing the holder 6 and the introduction pipe 8 andreplacing the sampling filter 7 with a new one.

The invention can be modified as follows.

-   (1) Although a cylindrical filter is used as the sampling filter 7    in the above-described embodiment, the invention is not restricted    to that. For example, the invention can be carried out in the same    manner in the case the sampling filter 7 is formed into a    column-like or a disk-like shape.-   (2) Although in the above-described embodiment, description is given    regarding the case of sampling the chlorinated organic compounds    such as dioxins and coplanar PCBs contained in a waste gas (a sample    gas) discharged out an incinerator of wastes, the sampling filter,    the sampling apparatus, and the sampling method of the invention may    be employed in the same manner also in the case of sampling the    chlorinated organic compounds contained in a fluid other than the    waste gas. For example, the sampling filter and the like of the    invention may be used in the same manner in the case of sampling the    chlorinated organic compounds contained in the atmospheric air and    the chlorinated organic compounds contained in water such as    industrial wastewater, seawater, freshwater, and tap water and the    like.

Incidentally, in the case of sampling the chlorinated organic compoundscontained in water such as industrial water, the target sample is aliquid sample. In this case, the liquid sample possibly contains varioustypes of the chlorinated organic compounds in particulate state, foamstate (that is, gas-liquid mixed state), and dissolved state (that is,dissolved-in-water state), the sampling filter of the invention cansimultaneously collect the various types of the chlorinated organiccompounds in a variety of such states and sample them from the liquidsample.

Hereinafter, the invention will be described in greater detail accordingto the examples. Here, for the sake of understanding, at firstcomparative examples will be described and then examples will bedescribed.

COMPARATIVE EXAMPLE 1

Coal based fibrous activated carbon with the average fiber diameter of 4μm in 5% by weight and carbon fiber with the average fiber diameter of13 μm in 95% by weight were mixed and a cellulose-based binder was addedto obtain a molding material. The obtained molding material was moldedinto a one end-closed cylindrical shape and the resulting molded bodywas heated to dry the cellulose-based binder. Consequently, acylindrical molded body (a sampling filter) having the weight of 2.3 gand the bulk density of 0.11 g/cm³ was obtained which was so adjusted asto have the outer diameter of 19 mm in the opening end side, the outerdiameter of 18 mm in the closed end side, the thickness of 5 mm, and thelength of 20 mm, respectively.

Using the obtained sampling filter, a collector 3 for the chlorinatedorganic compounds according to the above-described embodiment wasproduced. Using the collector 3, the sampling apparatus 1 according tothe above-described embodiment was produced. A sample gas (a waste gas)was sampled from a flue duct of an incinerator during incineration ofwastes using the sampling apparatus 1 to sample the various types of thechlorinated organic compounds such as dioxins and coplanar PCBscontained in the sample gas. The sampling conditions of the sample gaswere adjusted as the conditions standardized by the JIS K 0311: 1999.

Simultaneously, the sample gas (the waste gas) was sampled from the sameflue duct in the same conditions using a sample gas sampling apparatusequipped with an impinger (hereinafter referred as to an apparatusexemplified in JIS formulation) to sample the various types of thechlorinated organic compounds such as dioxins and the coplanar PCBscontained in the sample gas.

The sampled chlorinated organic compounds were extracted by the methodaccording to JIS K 0311: 1999 and quantitatively analyzed according tothe analysis method standardized in the same JIS standards. As a result,in the case the average concentration of carbon monoxide in the samplegas was 150 ppm or lower, the amount of the chlorinated organiccompounds sampled by the sampling apparatus employing the samplingfilter of this comparative example was found different from the amountof the chlorinated organic compounds sampled by the apparatusexemplified in JIS formulation by 3% but substantially same as thatsampled by the apparatus exemplified in JIS formulation. On the otherhand, in the case the average concentration of carbon monoxide in thesample gas was 510 ppm, the amount of the chlorinated organic compoundssampled by the sampling apparatus employing the sampling filter of thiscomparative example was found only 85% to the amount of the chlorinatedorganic compounds sampled by the apparatus exemplified in JISformulation. Consequently, if the carbon monoxide concentration in thesample gas increased, in other words, if the concentration of unburnedcarbon compounds increased in the sample gas, the sampling filter of thecomparative example was found difficult to collect some of chlorinatedorganic compounds contained in the sample gas.

COMPARATIVE EXAMPLE 2

Coal based fibrous activated carbon with the average fiber diameter of 4μm in 5% by weight, carbon fiber with the average fiber diameter of 13μm in 65% by weight, and glass fiber with the average fiber diameter of3 μm in 30% by weight were mixed and a cellulose-based binder was addedto obtain a molding material. The obtained molding material was moldedinto a one end-closed cylindrical shape and the resulting molded bodywas heated to dry the cellulose-based binder. Consequently, acylindrical molded body (a sampling filter) having the weight of 2.5 gand the bulk density of 0.13 g/cm³ was obtained which was so adjusted asto have the same sizes as those of Comparative example 1.

Using the obtained sampling filter, the chlorinated organic compoundscontained in a sample gas sampled from the flue duct in the same manneras Comparative example 1 were sampled and the results of theirquantitative analysis were compared with those obtained in the case ofsampling by the apparatus exemplified in JIS formulation. In the casethe average concentration of carbon monoxide in the sample gas was 150ppm or lower, the amount of the chlorinated organic compounds sampled bythe sampling apparatus employing the sampling filter of this comparativeexample was found different from the amount of the chlorinated organiccompounds sampled by the apparatus exemplified in JIS formulation by 3%but substantially same as that sampled by the apparatus exemplified inJIS formulation. On the other hand, in the case the averageconcentration of carbon monoxide in the sample gas was 550 ppm, theamount of the chlorinated organic compounds sampled by the samplingapparatus employing the sampling filter of this comparative example wasfound only 82% to the amount of the chlorinated organic compoundssampled by the apparatus exemplified in JIS formulation. Consequently,if the carbon monoxide concentration in the sample gas increased, inother words, if the concentration of unburned carbon compounds increasedin the sample gas, the sampling filter of the comparative example wasfound difficult to collect some of chlorinated organic compoundscontained in the sample gas.

EXAMPLE 1

An aqueous alumina dispersion containing about 20% by weight of granularalumina (an inorganic binder) was prepared and alumina fibers(containing 72% by weight of γ-alumina and 28% by weight of silica)having an average fiber diameter of 6 μm and an average aspect ratio of2,000 as fibers were added to the alumina dispersion and mixed well. Theobtained molding material was molded in a one end-closed cylindricalshape and sintered at 200° C. Consequently, a cylindrical molded body (asampling filter) having the weight of 8.5 g and the bulk density of 0.38g/cm³ was obtained which was so adjusted as to have the same sizes asthose of Comparative example 1. Incidentally, the glass fibers and thegranular alumina contained in the molded body were 5.7 g and 2.8 g,respectively.

The electron microscopic photograph of a part of the obtained moldedbody is shown in FIG. 5. From FIG. 5, the molded body was found having agas-permeability and fine mesh structure (three-dimensional meshstructure) in which alumina fibers were bound to one another by thegranular alumina, which is the inorganic binder.

Using the obtained sampling filter, the chlorinated organic compoundscontained in a sample gas sampled from the flue duct in the same manneras Comparative example 1 were sampled and the results of theirquantitative analysis were compared with those obtained in the case ofsampling by the apparatus exemplified in JIS formulation. In both casesthe average concentration of carbon monoxide in the sample gas was 150ppm or lower and the concentration was 650 ppm, the amount of thechlorinated organic compounds sampled by the sampling apparatusemploying the sampling filter of this example was found different fromthe amount of the chlorinated organic compounds sampled by the apparatusexemplified in JIS formulation by 1% but substantially same as thatsampled by the apparatus exemplified in JIS formulation. Consequently,regardless of the carbon monoxide concentration in the sample gas, inother words, regardless of the concentration of unburned carboncompounds in the sample gas, the sampling filter of this Example 1 wasfound capable of collecting various types of the chlorinated organiccompounds in both particulate and gaseous forms contained in the samplegas substantially similarly to the apparatus exemplified in JISformulation.

EXAMPLE 2

A cylindrical molded body (a sampling filter) having a gas-permeabilityand the same sizes as those of Example 1 was obtained by the sameoperation as that in the case of Example 1, except that alumina fibers(containing at least 95% by weight of γ-alumina) having an average fiberdiameter of 5 μm and an average aspect ratio of 2,400 as fibers wereused. The molded body had a weight of 7.9 g and the bulk density of 0.32g/cm³ and the alumina fibers and the granular alumina contained in themolded body were 5.3 g and 2.6 g, respectively.

Using the obtained sampling filter, the chlorinated organic compoundscontained in a sample gas sampled from the flue duct in the same manneras Comparative example 1 were sampled and the results of theirquantitative analysis were compared with those obtained in the case ofsampling by the apparatus exemplified in JIS formulation. In both casesthe average concentration of carbon monoxide in the sample gas was 150ppm or lower and the concentration was 650 ppm, the amount of thechlorinated organic compounds sampled by the sampling apparatusemploying the sampling filter of this example was found different fromthe amount of the chlorinated organic compounds sampled by the apparatusexemplified in JIS formulation by 1% but substantially same as thatsampled by the apparatus exemplified in JIS formulation. Consequently,regardless of the carbon monoxide concentration in the sample gas, inother words, regardless of the concentration of unburned carboncompounds in the sample gas, the sampling filter of this Example 2wasfound capable of sampling various types of the chlorinated organiccompounds in both particulate and gaseous forms contained in the samplegas substantially similarly to the apparatus exemplified in JISformulation.

EXAMPLE 3

A molded body obtained in Example 1 was further immersed in an aqueousdispersion containing 20% by weight of granular alumina dispersed andthen taken out and dried by heating at 200° C. Consequently, a moldedbody (a sampling filter) having a weight of 12.8 g and the bulk densityof 0.6 g/cm³ was obtained.

Using the obtained sampling filter, the chlorinated organic compoundscontained in a sample gas sampled from the flue duct in the same manneras Comparative example 1 were sampled and the results of theirquantitative analysis were compared with those obtained in the case ofsampling by the apparatus exemplified in JIS formulation. In both casesthe average concentration of carbon monoxide in the sample gas was 150ppm or lower and the concentration was 750 ppm, the amount of thechlorinated organic compounds sampled by the sampling apparatusemploying the sampling filter of this example was found different fromthe amount of the chlorinated organic compounds sampled by the apparatusexemplified in JIS formulation by 1% but substantially same as thatsampled by the apparatus exemplified in JIS formulation. Consequently,regardless of the carbon monoxide concentration in the sample gas, inother words, regardless of the concentration of unburned carboncompounds in the sample gas, the sampling filter of this Example 3 wasfound capable of sampling various types of the chlorinated organiccompounds in both particulate and gaseous forms contained in the samplegas substantially similarly to the apparatus exemplified in JISformulation.

EXAMPLE 4

A molded body obtained in Example 2 was further immersed in an aqueousdispersion containing 20% by weight of granular alumina dispersed andthen taken out and dried by heating at 300° C. Consequently, a moldedbody (a sampling filter) having a weight of 12.3 g and the bulk densityof 0.58 g/cm³ was obtained.

Using the obtained sampling filter, the chlorinated organic compoundscontained in a sample gas sampled from the flue duct in the same manneras Comparative example 1 were sampled and the results of theirquantitative analysis were compared with those obtained in the case ofsampling by the apparatus exemplified in JIS formulation. In both casesthe average concentration of carbon monoxide in the sample gas was 150ppm or lower and the concentration was 700 ppm, the amount of thechlorinated organic compounds sampled by the sampling apparatusemploying the sampling filter of this example was found different fromthe amount of the chlorinated organic compounds sampled by the apparatusexemplified in JIS formulation by 1% but substantially same as thatsampled by the apparatus exemplified in JIS formulation. Consequently,regardless of the carbon monoxide concentration in the sample gas, inother words, regardless of the concentration of unburned carboncompounds in the sample gas, the sampling filter of this Example 4 wasfound capable of sampling various types of the chlorinated organiccompounds in both particulate and gaseous forms contained in the samplegas substantially similarly to the apparatus exemplified in JISformulation.

Example 5

A cylindrical molded body having a gas-permeability and the same sizesas those of Example 1 was obtained by the same operation as that in thecase of Example 1, except that glass fibers having an average fiberdiameter of 4 μm and an average aspect ratio of 3,000 as fibers wereused. The molded body had a weight of 8.8 g and the bulk density of 0.37g/cm³ and the glass fibers and the granular alumina contained in themolded body were 6.1 g and 2.7 g, respectively.

The obtained molded body was further immersed in an aqueous dispersioncontaining 20% by weight of granular alumina dispersed and then takenout and dried by heating at 400° C. Consequently, a molded body (asampling filter) having a weight of 12.9 g and the bulk density of 0.62g/cm³ was obtained.

Using the obtained sampling filter, the chlorinated organic compoundscontained in a sample gas sampled from the flue duct in the same manneras Comparative example 1 were sampled and the results of theirquantitative analysis were compared with those obtained in the case ofsampling by the apparatus exemplified in JIS formulation. In both casesthe average concentration of carbon monoxide in the sample gas was 150ppm or lower and the concentration was 550 ppm, the amount of thechlorinated organic compounds sampled by the sampling apparatusemploying the sampling filter of this example was found different fromthe amount of the chlorinated organic compounds sampled by the apparatusexemplified in JIS formulation by 1% but substantially same as thatsampled by the apparatus exemplified in JIS formulation. Consequently,regardless of the carbon monoxide concentration in the sample gas, inother words, regardless of the concentration of unburned carboncompounds in the sample gas, the sampling filter of this Example 5 wasfound capable of sampling various types of the chlorinated organiccompounds in both particulate and gaseous forms contained in the samplegas substantially similarly to the apparatus exemplified in JISformulation.

EXAMPLE 6

A cylindrical molded body having a gas-permeability and the same sizesas those of Example 1 was obtained by the same operation as that in thecase of Example 1, except that silica fibers having an average fiberdiameter of 7 μm and an average aspect ratio of 1,500 as fibers wereused. The molded body had a weight of 7.2 g and the bulk density of 0.31g/Cm³ and the silica fibers and the granular alumina contained in themolded body were 4.7 g and 2.5 g, respectively.

The obtained molded body was further immersed in an aqueous dispersioncontaining 20% by weight of granular alumina dispersed and then takenout and dried by heating at 550° C. Consequently, a molded body (asampling filter) having a weight of 11.3 g and the bulk density of 0.58g/cm³ was obtained.

Using the obtained sampling filter, the chlorinated organic compoundscontained in a sample gas sampled from the flue duct in the same manneras Comparative example 1 were sampled and the results of theirquantitative analysis were compared with those obtained in the case ofsampling by the apparatus exemplified in JIS formulation. In both casesthe average concentration of carbon monoxide in the sample gas was 150ppm or lower and the concentration was 500 ppm, the amount of thechlorinated organic compounds sampled by the sampling apparatusemploying the sampling filter of this example was found different fromthe amount of the chlorinated organic compounds sampled by the apparatusexemplified in JIS formulation by 1% but substantially same as thatsampled by the apparatus exemplified in JIS formulation. Consequently,regardless of the carbon monoxide concentration in the sample gas, inother words, regardless of the concentration of unburned carboncompounds in the sample gas, the sampling filter of this Example 6 wasfound capable of sampling various types of the chlorinated organiccompounds in both particulate and gaseous forms contained in the samplegas substantially similarly to the apparatus exemplified in JISformulation.

The present invention can be carried out in variously modified formswithout departing from the true scope and the features of the invention.The above-described examples and embodiments are merely examples and arenot meant to be construed in a limiting sense. It is thereforecontemplated that the appended claims will cover any modifications orembodiments as fall within the true scope of the invention.

1. A filter for removing chlorinated organic compounds contained in afluid from the fluid flowing in a transportation pipe and sampling thechlorinated organic compounds, comprising: a fluid-permeable molded bodycontaining fibers and an inorganic binder for binding the fibers to oneanother, wherein the molded body is a cylinder having an opening toinsert the transportation pipe into one side and closed in the otherside.
 2. The filter according to claim 1, wherein the molded body has abulk density of 0.1 to 1 g/cm³.
 3. The filter according to claim 1,wherein the fibers are at least one kind of fibers selected from thegroup consisting of fibrous activated carbon, carbon fiber, glass fiber,alumina fiber, silica fiber and polytetrafluoroethylene fiber.
 4. Thefilter according to claim 1, wherein the inorganic binder has achlorinated organic compounds-adsorbing capability.
 5. The filteraccording to claim 4, wherein the inorganic binder is at least onecompound selected from the group consisting of alumina, zeolite andsilicon dioxide.
 6. The filter according to claim 1, wherein the fibersare activated alumina fibers and the inorganic binder is granularactivated alumina.
 7. The filter according to claim 6, wherein themolded body has a bulk density of 0.3 to 0.7 g/cm³.
 8. A method forproducing a filter for removing chlorinated organic compounds containedin a fluid from the fluid flowing in a transportation pipe and samplingthe chlorinated organic compounds, comprising the steps of: producing amolding material containing fibers and an inorganic binder for bindingthe fibers to one another, and obtaining a molded body by molding themolding material into a cylinder shape having an opening to insert thetransportation pipe into one side and closed in the other side and thensintering the molded material.
 9. The method for producing a filteraccording to claim 8, wherein the method further comprises a step ofimmersing the molded body in an aqueous dispersion of the inorganicbinder and then drying the molded body.
 10. A collector for collectingchlorinated organic compounds contained in a fluid, comprising: a pipefor transporting the fluid containing the chlorinated organic compounds,a filter of a fluid-permeable molded cylinder body having an opening inone side and closed in the other side and comprises fibers and aninorganic binder for binding the fibers to one another, and a containerfor housing the filter, wherein, the pipe is inserted into the openingfor passing the fluid from the pipe through the filter and the containerhas an outlet for discharging the fluid that passed through the filterto the outside.
 11. The collector according to claim 10, wherein thefilter has a bulk density of 0.1 to 1 g/cm³.
 12. The collector accordingto claim 10, wherein the fibers are at least one kind of fibers selectedfrom the group consisting of fibrous activated carbon, carbon fiber,glass fiber, alumina fiber, silica fiber and polytetrafluoroethylenefiber.
 13. The collector according to claim 10, wherein the inorganicbinder has a chlorinated organic compounds-adsorbing capability.
 14. Thecollector according to claim 13, wherein the inorganic binder is atleast one compound selected from the group consisting of alumina,zeolite and silicon dioxide.
 15. The collector according to claim 10,wherein the fibers are activated alumina fibers and the inorganic binderis a granular activated alumina.
 16. The collector according to claim15, wherein the filter has a bulk density of 0.3 to 0.7 g/cm³.